This present invention relates generally to manufacturing objects. More particularly, the invention relates to a method and structure for fabricating one or more landing pads for spatial light modulators. Merely by way of example, the invention has been applied to the formation of a landing pad structure fabricated from a dielectric layer coupled to a standoff structure. The method and device can be applied to spatial light modulators as well as other devices, for example, micro-electromechanical sensors, detectors, and displays.
Micro-electromechanical systems (MEMS) are used in a number of application areas. For example, MEMS have been used in micro-mirror arrays, sensors, and actuators. In some of these applications, a suspended member is attracted to an electrode upon application of an electrical force and restored to an original position by a restoring force. As the suspended member approaches the electrode, surface forces can exert influences on the MEMS. These surface forces are sometimes referred to as “stiction” forces, since in some MEMS, parasitic forces arise from a combination of MEMS components sticking together and from friction, thus the term stiction. These parasitic forces may be strong enough to overcome the restoring force, resulting in an undesirable adhesion of the suspended member to the electrode.
As merely an example, conventional MEMS have relied upon a variety of techniques to overcome such stiction forces. For example, certain devices have relied upon the coating of MEMS components and the use of complex mechanical structures. Unfortunately, these techniques also have limitations. For example, some coatings are difficult to deposit on small components and can require complex deposition equipment. Moreover, complex mechanical structures may have reliability and lifetime concerns.
In response to certain of these issues, some MEMS architectures, in particular spatial light modulator architectures, have provided landing posts attached to micro-mirrors present in arrays. Landing posts serve to reduce the contact area between the suspended member and the electrode surface. However, as with other approaches, reliability and lifetime concerns may be present in these designs.
Thus, there is a need in the art for methods and apparatus for fabricating improved landing pad structures for spatial light modulators.